code: def run_shell_cmd(cmd):
      print("> running shell command: %s" % cmd)
      ret = os.system(cmd)
      if ret != 0:
          printerr("shell command failed with error code %d" % ret)
  
file_path: pdftabextract/examples/schoolinspections_imageproc/extract.py
imports: import os
  import sys
  import re
  from pprint import pprint
  import numpy
  import cv2
  import matplotlib.pyplot
  from pdftabextract.common import read_xml, parse_pages, sorted_by_attr, list_from_attr
  from pdftabextract.textboxes import join_texts
label_desc: Use image node_id 2 for calling a global function with example usage: run_shell_cmd(cmd) without return types